The activation of the α-carbons of carboxylic esters and related carbonyl compounds to generate enolate equivalents as nucleophiles is one of the most powerful strategies in organic synthesis. We reasoned that the horizons of chemical synthesis could be greatly expanded if the typically inert β-carbons of saturated esters could be used as nucleophiles. However, despite the rather significant fundamental and practical values, direct use of the β-carbons of saturated carbonyl compounds as nucleophiles remains elusive. Here we report the catalytic activation of simple saturated ester β-carbons as nucleophiles (β-carbon activation) using N-heterocyclic carbene organocatalysts. The catalytically generated nucleophilic β-carbons undergo enantioselective reactions with electrophiles such as enones and imines. Given the proven rich chemistry of ester α-carbons, we expect this catalytic activation mode for saturated ester β-carbons to open a valuable new arena for new and useful reactions and synthetic strategies.

A completely atom-economical and redox-neutral catalytic amide synthesis from an alcohol and a nitrile is realized. The amide C-N bond is efficiently formed between the nitrogen atom of nitrile and the α-carbon of alcohol, with the help of an N-heterocyclic carbene-based ruthenium catalyst, without a single byproduct. A utility of the reaction was demonstrated by synthesizing (13)C or (15)N isotope-labeled amides without involvement of any separate reduction and oxidation step.

A substrate-independent selective generation of enolates over homoenolate equivalents in NHC-catalyzed reactions of enals and chalcones is disclosed. Acid co-catalysts play vital roles in control of the reaction pathways, allowing for individual access to diverse products from identical substrates.

Single particle collision is emerging as a powerful and sensitive technique for analyzing small molecules, however, its application in biomacromolecules detection, for example, protein, in complex biological environments is still challenging. Here, we present the first demonstration on the single particle collision that can be developed for the detection of platelet-derived growth factor (PDGF), an important protein involved in the central nervous system in living rat brain. The system features Pt nanoparticles (PtNPs) conjugated with the PDGF recognition aptamer, suppressing the electrocatalytic collision of PtNPs toward the oxidation of hydrazine. In the presence of PDGF, the stronger binding between targeted protein and the aptamer disrupts the aptamer/PtNPs conjugates, recovering the electrocatalytic performance of PtNPs, and allowing quantitative, selective, and highly sensitive detection of PDGF in cerebrospinal fluid of rat brain.

A structurally diverse set of polyfunctionalized carbazoles was efficiently synthesized in acceptable to excellent yields.